This invention relates generally to lock nuts, and more particularly to improvements in such nuts wherein cantilevered locking segments are permanently deflected or angled radially inwardly to resiliently grip the bolt threadably received by the nut.
In a typical nut of this type, the upper portion of the nut is segmented by slotting the threaded wall and then inwardly deflecting these segments toward the central axis. This permanent deflection of the locking segments is greatest at the exit end of the thread thus allowing more flexibility of these segments than the entry end of the locking device. These beam-like locking segments are essential to a good locking action and provide excellent flexibility while providing a frictional force on the flanks of the thread of the mating male fastener. This frictional force provides what is known as prevailing torque when there is relative rotation of the two elements. The relative rotation of the two elements and the slots between the locking segments, irrespective of the number of slots, cause early failure of both of the mating elements. Since the screw or bolt has an interference contact at the slots of approximately 90.degree. and the slots present sharp cutting edges, these slots act like a thread cutting die of the type used for cutting threads on a pipe, rod or bolt. The cutting edges consequently shave or cut plating or metal off the flanks of the mating screw or bolt. This soon causes galling and reduction of the pitch diameter of the screw or bolt and also an increase in the pitch diameter of the lock nut, so that there soon is a loss of the locking action of the nut, or complete seizing of the two mating elements.
There is need for an improved nut of this type, which is so constructed as to eliminate the cutting and galling action.